In his first campaign for the presidency, Barack Obama promised to reverse the worst excesses of the Bush administration's approach to terrorism – such as the use of torture, the rendition of terrorist suspects to CIA-run black sites around the globe, and the denial of basic legal rights to prisoners in Guantánamo – and to develop a counterterrorism policy that was consistent with the legal and moral tradition of the United States. In an address at the Woodrow Wilson Center in August 2007, Obama criticized the Bush administration for putting forward a "false choice between the liberties we cherish and the security we demand", and swore to provide "our intelligence and law enforcement agencies with the tools they need to track and take out the terrorists without undermining our constitution and our freedom".

As a candidate, Obama also promised to restore proper legislative and judicial oversight to counterterrorism operations. Rather than treat counterterrorism policy as an area of exception, operating without the normal safeguards that protect the rights of the accused, Obama promised that his approach "will again set an example for the world that the law is not subject to the whims of stubborn rulers, and that justice is not arbitrary."

Four years later, it is clear that President Obama has delivered a very different counterterrorism policy from that which he promised on the campaign trail. (Full disclosure: I was an adviser on the Obama campaign's counterterrorism expert group from July 2007-November 2008.) In fairness, he has delivered on a few of his promises, including closing the CIA-run "black site" prisons abroad and ordering that interrogations of all suspects be conducted according to the US army field manual, which proscribes many of the tactics widely considered torture. And some failures were not wholly his own: Obama's inability to close Guantánamo Bay was due more to congressional opposition and to an array of legal obstacles than to his own lack of initiative.

Yet, contrary to his campaign promises, Obama has left most of the foundations of Bush's counterterrorism approach intact, including its presumption of executive privilege, its tolerance of indefinite detention in Guantánamo and elsewhere and its refusal to grant prisoners in America's jails abroad habeas corpus rights. While the language of the "war on terror" has been dropped, the mindset of the Bush approach – that America is forever at war, constantly on the offensive to kill "bad guys" before they get to the United States – has crept into this administration and been translated into policy in new and dangerous ways.

This fact is clearly demonstrated in a recent New York Times article, which details how President Obama has become personally involved in an elaborate internal process by which his administration decides who will be the next victim of America's drone strikes. The article itself – clearly written with the cooperation of the administration, as the writers had unprecedented access to three dozen counterterrorism advisers – was designed to showcase Obama as a warrior president, thoughtfully wrestling with the moral issues involved in drone strikes, but forceful enough to pull the trigger when needed.

What it instead revealed was that the president has routinized and normalized extrajudicial killing from the Oval Office, taking advantage of America's temporary advantage in drone technology to wage a series of shadow wars in Afghanistan, Pakistan, Yemen, and Somalia. Without the scrutiny of the legislature and the courts, and outside the public eye, Obama is authorizing murder on a weekly basis, with a discussion of the guilt or innocence of candidates for the "kill list" being resolved in secret on "Terror Tuesday" teleconferences with administration officials and intelligence officials.

The creation of this "kill list" – as well as the dramatic escalation in drone strikes, which have now killed at least 2,400 people in Pakistan alone, since 2004 – represents a betrayal of President Obama's promise to make counterterrorism policies consistent with the US constitution. As Charles Pierce has noted, there is nothing in the constitution that allows the president to wage a private war on individuals outside the authorization of Congress.

The spirit of the constitution was quite the opposite: all of the founders were concerned, in varying degrees, with the risk of allowing the president to exercise too much discretion when declaring war or using force abroad. For this reason, the constitution explicitly grants the right to declare war to the Congress in order to restrain the president from chasing enemies around the world based solely on his authority as commander-in-chief. The founders would be horrified, not comforted, to know that the president has implicated himself in the killing of foreign nationals in states against which the Congress has not passed a declaration of war.

Beyond bypassing the constitution and the War Powers Act, the Obama administration has also adopted a dangerously broad interpretation of the legal right to use drone strikes against terrorist suspects abroad. According to his counterterrorism chief, John Brennan, the legal authority for the drone strikes derives from the Authorization for Use of Military Force (AUMF) passed by the Congress in September 2001 to authorize the attack on Afghanistan. He notes that there is "nothing in the AUMF that restricts the use of military force against al-Qa'ida to Afghanistan".

This interpretation treats the AUMF as a warrant to allow the president to use force against anyone at any time in a war without a defined endpoint.

Together with the bland assertion that the US has the right to self-defense against al-Qaida under international law, these legal arguments have enabled the president to expand drone operations against terrorist organizations to Yemen and Somalia, as well as to escalate the campaign against militant networks in Pakistan. To date, Obama has launched 278 drone strikes against targets in Pakistan. The use of drone strikes is now so commonplace that some critics have begun to wonder if the administration has adopted a "kill, not capture" policy, forsaking the intelligence gains of capturing suspects for an approach that leaves no one alive to pose a threat.

This vast, expansive interpretation of executive power to enable drone wars conducted in secret around the globe has also set dangerous precedent, which the administration has not realized or acknowledged. Once Obama leaves office, there is nothing stopping the next president from launching his own drone strikes, perhaps against a different and more controversial array of targets. The infrastructure and processes of vetting the "kill list" will remain in place for the next president, who may be less mindful of moral and legal implications of this action than Obama supposedly is.

For those Democrats who are comforted by the fact that Obama has the final say in authorizing drone strikes and so refuse to criticize the administration, ask yourself: would you be as comfortable if the next decision on who is killed by a drone was left to President Romney, or President Palin?

Also in contravention of his campaign promises, the Obama administration has worked to expand its power of the executive and to resist oversight from the other branches of government. While candidate Obama insisted that even terrorist suspects deserved their due process rights and a chance to defend themselves in some kind of a court, his administration has now concluded that a review of the evidence by the executive branch itself – even merely a hasty discussion during one of the "Terror Tuesdays" – is equivalent to granting a terrorist suspect due process rights. With little fanfare, it has also concluded that American citizens may now be killed abroad without access to a "judicial process".

What is also striking about Obama's embrace of drones and targeted killings is that he – who, during his 2008 campaign, displayed awareness that America's reckless actions abroad were damaging to its long-term interests – has become so indifferent to civilian casualties. According to statistics compiled by the Bureau of Investigative Journalism, at least 551 civilians have been killed in drone strikes in Pakistan, Yemen, and Somalia, though the figure could be much higher. Yet, the Obama administration has consistently argued that almost no civilians are killed in these strikes, despite independent assessments that put the number of civilians killed as much higher.

This claim is only possible because the administration has engaged in an Orwellian contortion of language, which assumes that anyone in the area of a drone strike must be "up to no good" and therefore a militant. This assumption of guilt by association, and the grotesque misuse of definitions to cover up the deaths of innocents, including children, has allowed the administration to inflate the number of successful "hits" it has, while playing down the number of civilian casualties.

Now emboldened by this apparent success and the lack of an outcry over deaths caused by drone strikes, the administration is proposing to loosen the standards for targeting in Yemen even further by approving so-called "signature strikes", in which attacks are launched on patterns of behavior rather than the known presence of a terrorist operative. These signature strikes are almost guaranteed to increase the number of civilian casualties, as they are far more likely to catch innocent people who happen to be in the wrong place at the wrong time.

The drone strikes are portrayed by the administration as successful because they are able to take out high-ranking terrorist operatives, such as Abu Yahya al-Libi . But such a portrayal conflates a tactical victory (killing one al-Qaida commander) with a strategic success (that is, dampening the growth of extremist movements in Afghanistan and Pakistan). It also rarely looks at the other side of the ledger and asks whether the drone strikes have jeopardized the stability of the governments of Pakistan and Yemen, possibly risking more chaos if they are overthrown.

During his first presidential campaign, Obama promised to control counterterrorism operations and to put them in their proper place as one piece of a wider set of relationships with other governments. But he has done the opposite, allowing short-term tactical victories against terrorist networks to overwhelm America's wider strategic priorities and leave its relations with key governments in a parlous state. His embrace of drones and his willingness to shoot first may also be policies that the US comes to regret when its rivals, such as China begin to develop and use their own drones.

Beyond simply failing to live up to campaign promises, the real tragedy of Obama's counterterrorism policy is that he has squandered an unprecedented opportunity to redefine the struggle against al-Qaida in a way that moves decisively beyond the Bush administration's mindset. Instead, he has provided another iteration of that approach, with a level of cold-blooded ruthlessness and a contempt for the constitutional limits imposed on executive power that rivals his predecessor.

Instead of restoring counterterrorism to its proper place among America's other foreign policy priorities, President Obama has been seduced by political expediency and the lure of new technology into adopting a policy that kills first and asks questions later. He may succeed in crippling al-Qaida and preventing some attacks today, but it is now harder than ever to believe that a young child in Pakistan hearing the whirring noises of drones above them will look up and see Obama's America as "the relentless opponent of terror and tyranny, and the light of hope to the world".